Three Thousand Motion-Confirmed L and T Dwarf Candidates from the Backyard Worlds:~Planet 9 Citizen Science Project
Abstract
The Backyard Worlds: Planet 9 citizen science project uses data from the Wide-field Infrared Survey Explorer to detect infrared objects with significant motion. In this work, we present the majority of the L and T dwarf candidates discovered through this effort. For each candidate, we provide proper motion measurements as well as optical, near-infrared, and mid-infrared photometry (when available), photometric spectral types and distance estimates. Three thousand and six new motion-confirmed discoveries are presented in this work, 2,357 with L-type photometric spectral types and 649 with T-type photometric spectral types. We also present an additional 80 objects as likely L or T dwarfs based on available photometry, but for which a significant motion measurement could not be obtained. We identify 28 objects in this sample as new comoving companions to higher-mass stars, and an additional 9 sources that are candidate binary systems made up of two ultracool dwarfs of L-type or later. Follow-up spectroscopic observations will be necessary to confirm spectral types and further characterize the sources discovered through this project. This work presents the largest single sample of motion-confirmed L and T dwarf discoveries to date, which would more than double the number of known L and T dwarfs, if confirmed. We wish to sincerely thank our citizen scientist collaborators for their monumental efforts that have directly impacted this project's success.
Keywords
Cite
@article{arxiv.2604.01323,
title = {Three Thousand Motion-Confirmed L and T Dwarf Candidates from the Backyard Worlds:~Planet 9 Citizen Science Project},
author = {Adam C. Schneider and Marc J. Kuchner and Jacqueline K. Faherty and Aaron M. Meisner and J. Davy Kirkpatrick and Adam J. Burgasser and Daniella Bardalez Gagliuffi and Thomas P. Bickle and Dan Caselden and Sarah L. Casewell and Jonathan Gagné and Easton J. Honaker and Frank Kiwy and Federico Marocco and Austin Rothermich and Nikolaj Stevnbak Andersen and Lizzeth Ruiz Arroyo and Bruce Baller and Paul Beaulieu and John Bell and Martin Bilsing and Troy K. Bohling and Guillaume Colin and Giovanni Colombo and Sam Deen and Alexandru Dereveanco and Kevin Dixon and Hugo A. Durantini Luca and Deiby Flores and Christoph Frank and Christopher Fulvi and Michael Gallmann and Jean Marc Gantier and Konstantin Glebov and Léopold Gramaize and Leslie K. Hamlet and Ken Hinckley and Kevin Jablonski and Peter A. Jałowiczor and Martin Kabatnik and Peter Kasprowitz and K Ly and David W. Martin and Naoufel Marzak and Alexander McColgan and Neil J. McEwan and Marianne N. Michaels and William Pendrill and Stéphane Perlin and Ben Pumphrey and James Rabe and Henry Raway and Walter Ruben Robledo and David Roser and Animesh Roy and Arttu Sainio and Vincent Schindler and Manfred Schonau and Jörg Schümann and Karl Selg-Mann and Andrea Serio and David Sirbescu-Stanley and Patrick Smith and Andres Stenner and Christine Sunjoto and Christopher Tanner and Melina Thévenot and Vinod Thakur and Mayahuel Torres Guerrero and Maurizio Ventura and Nikita V. Voloshin and Jim Walla and Zbigniew Wȩdracki and Bailey Weyandt and Breck Wilhite and Spartacus Zitouni},
journal= {arXiv preprint arXiv:2604.01323},
year = {2026}
}
Comments
Accepted to AJ